A digital timing system for a small animal respiration pump

A digital timing system has been developed to control the airflow from a respiration pump used in small animal pulmonary measurements. Three separate periods of up to 10 sec may be selected with millisecond resolution using thumb-wheel switches. A modular design using CMOS technology minimized the number of interconnections among the various parts of the system. A larger number of timing channels, longer time periods, and greater time resolution may be achieved by directly extending the existing design.